Automatic telephone system



May 6 1924. 1,493,254

J. ERICKSON AUTOMATIC TELEPHONE SYSTEM Filed Oct. 21, 1918 2Sheets-Sheet l Julm EZEKSUTZ.

'HZTH:

May 6 1924.

J. ERICKSON AUTOMATI C TELEPHONE SYSTEM Filed Oct. 21, 1918 2Sheets-Sheet 2 Juhn .ErzcKsuz'z.

Patented May e, 1924.

UNITED STATES 1,493,254 PATENT, OFFICE.

JOHN ERICKSO'N, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRICCOM- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

-AUTOMATIC TELEPHONE SYSTEM.

Application filed October 21, 1918., Serial No. 259,062.

To all whom it may concern:

Be it known that I, JOHN ERIoKsoN, a citizen of the United States ofAmerica, and a resident of Chicago, county of Cook,

State of Illinois, have invented certain new and useful Improvements inAutomatic Telephone Systems, of which the following is a specification.

My invention relates in general to auto- 1 matic telephone systems andmore specifically to an improved type of automatic switch to be used ina system of this type for extending connections from one subscribersline to another. One of the objects of my invention is to provide amechanism for extending the lines of a subscriber in the simplest mannerpossible and to provide such a mechanism which is novel in action andwhich while meeting all the requirements ofsuch service, has a muchlonger life than mechanisms previously employed and has a centainty ofaction which is very desirable.

In the well known Strowger type of automatic switch which has been usedin the past one of the chief objections has been to the use of theratchet and pawl action for raising and rotating the w1pers. This actionis quite noisy and at the same time is apt towear out on account of thejar and rubbing action of the pawls against the ratchet, also theimpulses from the subscriber must'be of a certain length and strengthand the magnets for operating the pawls must be strongand therefore useup considerable current.

In order to overcome these difliculties I have devised an improved andnovel switch operating mechanism and method of control therefor which ishighly efiicient and which at the same time operates accurately tocontrol the movement of the wipers of a switch, whether the controllingimpulses are uniform in strength and speed or not,'thus preventing agreat deal of the trouble in getting false connections and wrongnumbers, when the impulses vary from standard due to leakage or'too muchcapacity or resistance in a line circuit.

Having described my invention in general I will now describe theoperation of one embodiment of my invention as shown in the accompanyingdrawings, in which,

Figure 1 is a side view of an automatic switch operated in accordancewith my invention.

Figure 2 is a front view of the apparatus shown in Fig. 1. I

Figure 3 is an enlar ed view showing the operating magnets an theirspecial armature more clearly. G 1

F i 4 is a cross section along the line A- in Fig;

3. w Figure 5 s owsa circuit diagram of-the switch as used inestablishing a connectionfnom one substation to another. The switch H,Figure 5, has an operating mechanism such as shown in Figures 1, 2, '3,and 4.

Fig. 6 shows the arrangement of the contacts in the bankof the switch.

Referring now to Figure 1, in order to simplify the ex lanation of themechanism I have shown t e same in connection with a simple one motionrotary switch such as might be used in an installation of a P. A. X. offrom 25 to 50 lines. The type of switch shown is that having a pluralityof wipers which rotate over a series of contact sets, one after theother, until a desired line is located and which ,are then released andreturned, to normal by. means of a spiral spring. The leads orconnections to the wipers consist of brushes which 'rub on the centerportion of each wiper.

In order to operate these wipers I provide a gear wheel 2, rigidlymounted on the shaft carrying the wipers and cooperating with a wormgear 3 which drives the gear wheel. This worm gear 3 is normally in meshwith the teeth of gear 2 and is pivoted at one end in the armature 4 ofa release magnet 5 and at the other end has a flexible connection withthe armature of a pair of op erating magnets 6. Any rotary movement ofthe worm gear 3 drives the wipers forward toward another set ofcontacts.

The operating magnets 6 with their armature are shown more; clearly inFi res 3 and 4. These magnets are mounted e tween a pair ofbrassbrackets 7: and 8, each magnet having a pair of pole pieces 9 and10 and 11 and 12, respectlvely, the inner ends of which are bent towardeach other as shown. The armature of these two magnets is of peculiardesign and is pivoted at points 13 and 14 in the brass plates 7 and 8.This armature consists of a shaft 15 having a brass piece 16 fastened toone side thereof by means of holes in its bent over end, and

oured to the ends of the brass piece 16 is an iron part 18 which is soformed that one edge of its outer surface is very close to the polepieces 11 and 12 or 9 and 10 when rotated, while its other edge is muchfarther away from the pole pieces, as shown in Figure 4. This wholearmature being of a cylindnical shape, may revolve inside the curvedpole pieces 9 and 11 at one end and 10 and 12 at the other end.

Now assume. the armature to be resting as shown in Figs. 3 and 4 withthe iron part 18 thereof close to the pole pieces 11 and 12. It will beseen that the thinner edge thereof is nearest to the left hand magnet 6.Now when the left hand magnet is energized the armature will be rotatedin the direction of the arrow in Fig.4. As the armature turns it will beseen that the thicker part of the part '18 gets nearer to the polepieces so that the magnet always has something to pull against and willcontinue to draw the armature around a complete half turn until the part18 stands with its thick edge flush with the upper or back edge of polepieces 10 and 9, Figs. 3 and 4, so that the thin edge will now be closerto pole pieces 11 and 12 than the heavy edge. Then if the right handmagnet 6 be energized it will be seen that the armature will again bedrawn about its axis in .the direction of the arrow. The armature istherefore given one full turn by the energization of first one and thenthe other of its controlling magnets. The worm gear 3 and the gear wheel2 are so. related thatone comple'teturn of the armature of the magnets 6moves the wiper of the switch, through the worm and gear, one step ontothe next set of contacts so that 4 impulses will send the wipers 2steps, that is,4 impulses delivered alternately to the operatingmagnets.

As the wipers are thus advanced by the worm 3, tension is stored up inthe spiral spring 19 which winds around the wiper shaft. After thewipers have been rotated in this manner they may be released by theoperation of the release magnet 5. This magnet 5, as explained, has anarmature one end of which acts as a pivot for the worm 3.

4 Now when magnet 5 is energized the worm 3 is carried away from theteeth of the gear 2 and the spring 19 acts on the shaft, to rotate thewipers back to normal position. An arm or normal post 20 is rigidlysecured to the wiper shaft and controls the off normal springs. As thewipers advance this arm 20 leaves said springs and allows them to comeinto'contact in pairs and again forces them apart when the wipers arereleased. It will switch operating motor mechanism which moves thewipers always in one direction in response to impulses without jar ornoise and consequently with very little friction or wear on the parts.Also that the worm gear 3 acts as a driving gear to advance the wipers,holds them in their advanced position, and is again operated to releasethe wipers.

:thus be seen that I have provided a novel Referring now to Figure 5, Iwill explain 7 the operation of a system using a switch such as shown inFigs. 1,2, 3 and4. When the subscriber at substation A removes hisreceiver a circuit is closed for the line relay 25 in series with thecalling line. Relay 25 energizes and closes a circuit from groundthrough springs 26 and 27, relay 31, and springs 32 and 33 to battery. 7Relay 31 connects ground throughsprings 34 to the private normalconductor 37, and prepares a circuit for slow relayt38 and magnet 41 atsponds to the left hand magnet 6 in figures 2, 3 and 4. Magnet 41, uponenergizing, draws the armature around one half turn as explained inconnection with Figure 3 and thereby rotates the worm 3 (Fig.1)

sufliciently to move the wipers 47, 48 and- 49 half wa to 'the first setof contacts in the bank 0 the switch. As a result of this movement ofthe shaft and wipers, the off normal post 20 is moved away from the offnormal springs 50 and 51 which close contact and prepare circuits forthe release magnet 5 and switching relay 52, respectively. Now as relay25 again energizes, a

circuit is closed from ground through springs 26 and 27, springs 53,springs 54, springs 55 and 56, and magnet 42 to battery. As beforepointedout, magnet 42 draws the armature around anotherhalf turn untilthe iron portion thereof lies against its pole piece, and thereby,through the action of worm gear 2, drives the wipers 47. 48 and 49 ontothe first set of bank contacts. It will therefore be seen that onedeenergization and energization of the line relav 25 in response to asingle impulse from the calling device, operates to send two impulses tothe operating magnets of the switch, one to one magnet. and one to theother, and that these two impulses operate the switch to step the wipersone step. It will be understood that the relays 31 and 38 being slowacting, remain energized during the operation of relay 25. As soon asrelay 25 comes to rest energized, relay 38 will fall back. Relay 38,while energized, maintains the circuit of relay 43 open at springs 58,opens the circuit from the private wiper 49 at springs 59, maintains thecircuit of magnet 42 closed at springs 53, and completes a circuit ofthe slow relay at springs 61, extending from ground through springs 62,springs 61, springs 63 and 64, springs 65, and relay 60 to battery.Relay 60 now energizes over this circuit to prepare a circuit for relay66 at springs 67, opens the circuit of relay 52 at springs 68, opens onepoint at springs 69 in the circuit of the lower windingof the backbridge relay 73, prepares a locking circuit for itself through springs70 in case the called line is busy, opens springs 71, and closes onepoint in the busy signalling circuit at springs 72.

Assuming now that any lineis called whose number is less than 10, thenthe first series of impulses will operate the magnets 41 and 42 to stepthe wipers 47, 48 and 49 into engagement with the contacts connected tothat line. Relay 60, being slow acting,

remains energized for a time after the impulses cease and after relay 38opens the springs 61, so that, in case the called line is busy, and aground is present on the contact with which private wiper 49 connects,

an energizing circuit will be closed from ground through wiper 49,springs 59, springs 74 and 75, springs 67, and upper winding of relay 66to battery. Relay 66 energizes and locks itself to ground throughsprings 76, closes one point in the circuit of relay 73 at springs 77,closes another point at springs 78 in the locking circuit of the relay60, and connects the busy tone circuit from springs 72 to one side ofthe talking circuit. As a result of this operation it will be seen thatrelays 60 and 66 remain locked up and a busy tone is connected to thecalling subscribers line circuit.

Assuming, however, that the called line is idle, then as soon as theimpulses cease and relay 38 falls back, relay 66 not having energized inthis case, relay 52 will be energized over a circuit. extending frombattery through said relay, ofi' normal springs 51,

springs 79, springs 68, and ground through springs 80. Relay 52 opensthe circuit of relay 60 at springs 65, connects ground to the privatewiper 49 through spring 74 and its front contact, opens the circuit ofthe operating magnets at springs 46 and 54 and connects the called lineto the ringing circuit through springs 81 and 82 and springs 83. Ringingcurrent will now flow from the ringing interrupter R through springs 84and 85, through springs 86, springs 81 and 82. wiper 48, through. thebell of the called substation, back over wiper 47, springs 83,

springs 87 and 88, and upper winding of ring out off relay 66 tobattery. As soon as the called subscriber answers, relay 66 energizesover this circuit in series with the talking circuit of the called line,and disconnects the ringing circuit from the called line and cuts theline through to the back bridge relay 73. Relay 66 also closes a lockingcircuit for itself at springs 76, to ground through springs 80, andconnects ground through spring 78 and its front contact to the holdingcircuit of relay 52 and through spring 74 and its frontcontact to theprivate wiper. Back bridge relay 73 now energizes in series with thecalled line and opens springs 79. Conversation may now be carried onover the heavy conductors shown and when the conversation is com pleted,the release is accomplished as follows: Relay 25 deenergizes and opensthe circuit of relay 31, which in turn falls back to close the circuitof release magnet 5 over a circuit from ground through springs 26 and45, through springs 39 and 89, off normal springs 50 and relay 5 tobattery. Release magnet 5 attracts its armature to draw the worm gear 3out of engagement with the gear 2. As shown in Fig. 1, this worm gearhas a flexible joint or spring joint which permits it to be thus movedby the armature 4. As. soon as the worm disengages gear 2, said gear isdrawn back to its norma position by the spiral spring 19 and uponreaching normal the normal post 20 engages and operates the springs 50and 51 and thereby opens the circuit of magnet 5. A further result ofthe operation of magnet 5 is the opening of springs 55 and 56 andclosing of springs 55 and 57. This closes the circuit of operatingmagnet 42 and if the armature has by any chance been left in halfwayposition, this insures that it will always rest at normal so that theinitial impulse of the next call which always comes to magnet 41, willalways be effective to move the wipers the desired half step.

So far I have explained the operation of the switch when from one to tenimpulsesare sent to operate the same. As it is well known that-the usualcalling device is of the ten impulse type it will be understood thatsome method must be devised for taking care of the calls up to No. 25 asthis will necessitate more than "one operation of the dial. I have shownthe arrangement of'the contacts in the bank of the switch in Fig. 6. Nowif it is desired to call the number 12 contact or line then first tenimpulses will be delivered to the switch to step the wipers to thecontact marked 0 or tenth contact and then two impulses will be sent tostep the switchto the second contact beyond the 0 contact, or if thetwenty second contact or line is desired two sets of ten impulses aresent to the switch to step it first to the 0 contact and then to the 00contact and then two impulses step the switch to the second contactbeyond the 00. The Wipers normally stand on the first contact shown andin order to prevent wrong numbers because'of an extra impulsetransmitted by the receiver hook when the receiver is removed I haveconnected the second contact to the busy signaling machine so'that if asingle impulse is sent in the switch will stop on the contact marked 1and give the calling subscriber a busy signal.

Referring now to Fig. 5, I have shown the method by which I prevent theoperation of the relay 52 and the subsequent cutting ofi' of theoperating magnets when the switch stops between series of impulses onthe'O or 00 contacts. I have shown just below the wiper 48 one of theline contacts of the O and 00 contacts which is connected through aresistance to ground. Now when the wipers come to rest'between theseries of impulses and wiper 48 rests upon the contact 90, then acircuit is closed from ground through resistance 91, contact 90, wiper48, spring 81.and its back contact, springs 71, springs 92, and throughthe upper winding of relay 73 to battery. Relay 73. now energizes andopens the springs 79 in the circuit of relay 52, so that relay 52 willnot energize and open the circuit of the operating magnets at springs 46and 54.

As soon as the next series of impulses come in the circuit of relay 73is of ..c ourse broken at wiper 48 and if ten more impulses are sentthev circuit of relay 73 will again be closed at the 00 contacts. I Itwill be seen therefore that I have provided a novel and eflicient switchoperating, mechanism which is in the nature of a motor operated byimpulses and having a pair of operating magnets operated alternating torotate a shaft always in the same direction to step a series of wipersstep by step over a series of contacts. Also the gear or steppingarmature which is used to rotate the wipers is used both as a holdingand a release pawl. It will be understood that I have shown only onemodification of my invention to illustrate the same and that othermodifications in the method of control will readily suggest themselvesto those skilled in the art and come under the scope of my invention.

'Having fully described and ascertained the features and aspects of myinvention, what I consider to be new and desire to have protected byLetters Patent will be pointed out in the appended claims.

What I claim as my invention is:

1. In a telephone system, an automatic switch, wipers for said'switch, amotor for driving sald wipers consisting of a pair of operating magnets,having a; common rotatable armature, and means for energizing saidmagnets alternately to move said armature always in one direction tomove said wipers. I

2. In a telephone system, an automatic switch, wipers for said switch, amotor for driving said wipers consisting of a pair of operating magnetshaving a common rotatable armature, and means forenergizing said magnetsalternately to move said ar-' driving said wipers consisting ofa pair ofoperating magnets having a common rotatable armature, and means forenergizing said magnets alternately to move said ar- 'mature always inone direction to move said wipers in response to a single" series ofimpulses.

5. In a telephone system,-an automatic switch, wipers for said switch, amotor for driving said wipers consisting of a pair of operatmg magnetshaving a common rotatable armature, and means for energizing saidmagnets alternately to move said ar-v mature always in one direction tomove said wipers in response to a plurality of series of impulses.

6. In a telephone system, an automatic switch, wipers for said switch, amotor for driving said wipers consisting of a pair of operating magnetshaving a common rotatable armature, and means for energizing saidmagnets alternately to move said armature always in one direction tomove said wipers step by step in response to a plurahty of series ofimpulses.

7. In a telephone system, an automatic switch having wipers, a shaft formoving said wipers, a pair of magnets having a commonrotatable armaturefor driving said shaft, and means for operating said magnets alternatelyto move said armature always in one direction to operate said shaft in astep by step manner to drive the Wipers.

8. In a telephone system, an automatic switch having wipers, contactsaccessible to said wipers divided into groups, a motor for driving saidwipers over said contacts, said motor consisting of a'pair of magnetshaving a common rotatable armature,

means for delivering a series of impulses to said motor, and for causingeach successive impulse to operate alternate ones 'of'said magnets, andmeans controlled by the alternate operation of said magnets to move saidcommon armature to which said shaft is geared, and means fortransmitting an impulse to first one and then the other of said magnetsto step said shaft one step.

10. In a telephone system, an automatic switch, wipers for said switch,a motor consisting of a pair of magnets for operating said wipers, acommon-armature for said magnets, a shaft geared to said armature, saidwipers directly controlled by said shaft, and means for operating firstone magnet and then the other to rotate'the shaft and move the wipersone step.

11. In a telephone system, an automatic switch having wipers, a gear fordriving said wipers, a motor for driving said gear always in the samedirection consisting of a pair of magnets, means for delivering aplurality of impulses to said motor to operate said magnets alternatelyand means controlled by the alternate operation of said magnets foroperating said gear to drive the wipers in a step by step manner.

12. In a telephone system, an automatic switch having wipers, a gear fordriving said wipers, a motor for driving said gear consisting of a pairof magnets, means for delivering a plurality of impulses to said motorto operate said magnets alternately means controlled by the alternateoperation of said magnets for operating said gear to drive the wipers ina step by step manner, and means for disengaging said gear from thewipers to release the wipers.

13. In a telephone system, an automatic switch having wipers, a wormgear for driv- :ing said wipers normally ,in engagement with saidwipers, a pair of magnets for driving said gear, means for operatingsaid magnets alternately to drive said gear in one direction and a.magnet for removing said gear from engagement with the wipers to releasethe wipers from an advanced position.

- 14. In a telephone system, an automatic switch having a line relay andwipers, a motor for driving said wipers consisting of a pair of magnetshaving a common rotatable armature, means for operating said line relayin response to impulses to control said motor, each energization of saidline relay causing the operation of one of said magthe medium of sainets and each .deenergization of said relay causing the energization ofthe other of said magnets, the energization of both magnets causing asingle ste of said wipers through armature.

15. In a telephone system, an automatic switch, a wiper carrying elementtherefor,

and motor for moving said element, a shaft for said motor, said shaft incontinuous engagement with said element while the element is moved aplurality of steps and said motor operated by impulses of direct currentto' move the element in its steps, and means for disengaging said shaftfrom said element to release the switch.

16. In a telephone system, an automatic switch, having an operatingmagnet consisting of a pair of magnets having a common armature which isrotatable always in one direction, and carrying -a worm gear on one endthereof, means for operating the'switch through the medium of saidmagnets and gear, and means for disassociating said Worm gear from theswitch to release the switch. Q

17. In an automatic switch, a motor magnet comprising two coils, a linerelay for transmitting impulses to said coils alternately, an armaturerotating continuously in the same direction responsive to the alternateenergization of said coils, a wiper supporting element for said switch,and a reduction gear coupling the said armature and element together.

18. In an automatic switch, a motor magnet comprising two coils, a linerelay for transmitting impulses to said coils alternately, an armaturerotating continuously in the same direction responsive to the alternateenergization of said coils, a rotatable wiper shaft for said switch, anda reduction gear coupling the said armature and shaft together.

19. In an automatic switch, a motor magnet comprising two coils, a linerelay for transmitting impulses to said coils alternately, an armaturerotating continuously in the same direction responsive to the alternateenergization of said coils, a rotatable wiper shaft for said switch, aspring tending to maintain said shaft in a fixed position, and a wormgear coupling the said armature to said shaft to rotate the same againstthe tension of said spring, the said worm gear serving to preventretrograde movement of the shaft when said coils are not energized.

20. In an automatic switch, a motor magnetcomprising two coils, a linerelay for transmitting impulses to said coils alternate ly, an armaturerotating continuously in the same direction responsive to the alternateenergization of said coils, a rotatable wiper shaft for said switch, aspring tending to maintain said shaft .in a fixed position, a worm gearcoupling the same armature to said shaft to rotate the same against thetension of said spring, the said worm gear serving to prevent retrogrademovement of the shaft when said coils are not energized, andelectro-magnetic means for separating the elements of the worm gear whenthe switch and shaft together. 1

22. In an automatic switch, an individual motor magnet, a llne relay fortransmitting impulses to said magnet, an armature for sa1d magnetrevolving contlnuously 1n the same direction responsive to saidimpulses, a rotatable wiper shaft for said switch, and

" means for coupling said armature to said shaft, said means comprisinga worm gear ,which operates to drive the shaft when the armature isrevolving and to prevent the return movement of the shaft when thearmature is standing still.

23. In an automatic switch, two rotatable shafts disposed at rightangles to each other,

wipers mounted on one of said shafts, a mo-.

tor for driving the other shaft, said motor comprising magnets and anarmature mounted on said shaft for rotation between the poles of saidmagnets, a line relay for transmitting impulses to'the motor magnets torotate the armature shaft, and means for causing the armature shaft torotate the wiper shaft.

Signed by me at Chicago, Cook County, State of Illinois, this 19th dayof October,

JOHN ERIG'IKSON.

